Growl is a popular notification system for Mac OS X that throws up those fading pop-up windows in the upper right corner of the screen. It’s a nice add on to OS X, and tons of other applications use Growl as their notification system.

Then Mac OS X 10.7 came out, and Growl went from being open source to closed, and now it costs $2 to get the newest features in addition to Lion compatibility. Right? Wrong. Growl Fork, as the name implies, is a fork of Growl from the last open sourced version, and best of all, it includes Mac OS X Lion compatibility. If you don’t need the newer features in the official version and just want compatibility with Lion and your apps to continue receiving notifications, Growl Fork works just fine.

Install Growl Fork and it’ll appear in your System Preferences as usual, ready for configuration and with all of the settings that you had before in Snow Leopard. Again, it doesn’t have the newest features from the newest App Store version, but it works great and is completely free.